This week’s top 25 list ranks the region’s largest general contractors based on Triad billings, with Frank L. Blum Construction Co. climbing three spots to No. 1 versus last year. But for this section, we took the stats a little further by comparing just how much each firm’s Triad billings grew between 2012 and 2013. Below, we take a look at firms on the list notching the greatest increases on a percentage basis.